1. Field of the Invention
The present invention relates to controlling printing of a barcode, and more particularly, to a printing control method and a printing control apparatus utilizing a line light source detection result of a barcode.
2. Description of the Prior Art
A general barcode detection method applies a point light source as a detection apparatus which emits light and so that a light signal reflected from a barcode can be received for the subsequent detection process. However, a point light source (e.g., a laser beam source) is not a common product, and usually is expensive. If a more common and cheaper line light source (e.g., general fluorescent light) is utilized to perform detection, diffraction interference occurs and the correct detection result cannot be derived.
Generally, grading parameters of a barcode printed from a printing apparatus, for example, symbol contrast, decodability and barcode width growth can be examined by a verifier, and those derived grading parameters are fed back to the printing apparatus to further adjust printing parameters of the printing apparatus in order to obtain better printing quality. For example, please refer to FIG. 1, which is a diagram of applying a point light source to adjust a printing apparatus 110 with conventional technology. After the printing apparatus 110 prints out a barcode BC, a point light source detection element 120 will process the barcode BC to obtain a point light source detection result D_P, i.e., a reflectance of the barcode BC under the point light source. Next, a verifier 130 within the printing control apparatus 100 will receive the point light source detection result D_P, and generate a verification result R_P transmitted to a control element 140, and the control element 140 will adjust printing parameters of the printing apparatus 110 according to the verification result R_P in order to derive better barcode printing results.
Please refer to FIG. 2, which is a diagram of applying a line light source to adjust the printing apparatus 110 with conventional technology. The difference between FIG. 1 and FIG. 2 is that a line light source detection element 150 is utilized in FIG. 2 to process the barcode BC to derive a line light source detection result D_L, the verifier 130 will receive the line light source detection result D_L and derive grading parameters about the barcode BC according to all the reflectance within the line light source detection result D_L, so as to generate a verification result R_L to the control element 140. The control element 140 will then adjust printing parameters of the printing apparatus 110 according to the verification result R_L.
Please refer to FIG. 3 in conjunction with FIG. 1 and FIG. 2. FIG. 3 is a diagram of the barcode BC, the point light source detection result D_P and line light source detection result D_L both corresponding to the barcode BC. From FIG. 3, the inherent figure characteristics (i.e., those white identification bars and black identification bars arranged alternately with different widths) will be converted into different data according to a different luminance value of each identification bar, i.e., the point light source detection result D_P and line light source detection result D_L shown in FIG. 3. Although the point light source detection result D_P and line light source detection result D_L have similar data, the point light source detection result D_P is slightly higher than the line light source detection result D_L at high reflectance (for example, a white identification with high luminance). This is because diffractions from other places (for example, the black identification bars around the white identification bars) interfere with the detection result, and at low reflectance, those two detection results have no obvious difference. Furthermore, the width of each identification bar derived according to the line light source detection result D_L is also different from the one derived according to the point light source detection result D_P due to diffraction. In addition, since a typical line light source has less light intensity than does a point light source, the verifier 130 will occur more errors when processing the line light source detection result D_L than when processing the point light source detection result D_P. Therefore, a typical verifier usually does not tend to utilize a line light source for detection and adjusting printing parameters of a printing apparatus.